Biomedical subjects
Publications and source records attributed to Si Zhang.
A new phenylethanoid glycoside, 2-(3-methoxy-4-hydroxylphenyl) ethyl-O-2",3"-diacetyl-alpha-L-rhamnopyranosyl-(1-->3)-4-O-(E)-feruloyl-beta-D-glucopyranoside, was isolated from the aerial parts of Clerodendrum inerme (L.) Gaertn, together with monomelittoside, melittoside, inerminoside A1, verbascoside, isoverbascoside, campneoside I. Their structures were determined by spectroscopic methods.
Two unique 8,9,30-phragmalin ortho esters, xyloccensins O (1) and P (2), were isolated from the mangrove plant Xylocarpus granatum. They are a new type of ortho ester of phragmalin. The structures were determined by spectroscopic and single-crystal X-ray diffraction techniques. The biogenetic pathway to these new phragmalins was also proposed. [structure: see text]
Ten phenylethanoid glycosides, including two new ones, isolated from the aerial parts of the mangrove plant Acanthus ilicifolius were identified. The first complete assignments of the 1H and 13C NMR chemical shifts for these glycosides were achieved by means of 2D NMR techniques, including 1H-1H COSY, TOCSY, HSQC and HMBC spectra.
Three new briarane diterpenes, juncins O-Q (1-3), along with five known briaranes, praelolide, junceellin A, gemmacolide A, gemmacolide B, and junceellolide D, were isolated from the EtOH/CH(2)Cl(2) extracts of the South China Sea gorgonian coral Junceella juncea. The structures of 1-3 were established by extensive spectroscopic analysis, including 1D and 2D NMR data.
A new steroidal glycoside--4'-O-acetyl-3-O-[beta-D-arabino-pyranosyl-oxy]-cholest-5-ene-3beta,19-diol (1), and a new glycerol derivative--1,2-O-[2'-hydroxyoctadecyl]-glycerol (2), along with 16 known compounds were isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian coral Junceella juncea. The structures of 1 and 2 were established by extensive spectroscopic analysis, including 1D and 2D NMR data.
Five glycerol derivatives (1-5) and three sterols (6-8) were isolated from the EtOH extraction of the brown alga of Sargassum parvivesiculosum. On the basis of spectroscopic methods, their structures were elucidated as 1,3-di-O-[2',2'-di-(p-phenylene) isopropylidene] glycerol (1), (2S)-1-O-heptatriacontanoyl glycerol (2), (2S)-1,2-di-O-palmitoyl-3-O-(6-sulpho-alpha-D-quinovopyranosyl) glycerol (3), (2S)-1-O-palmitoyl glycerol (4), (2S)-1,3-di-(O-palmitoyl)-2-O-octadecanoyl glycerol (5), 24-ethylcholest-5,23Z-dien-3beta,28zeta-diol (6), 24-vinylcholest-5-en-24zeta-hydroperoxy (7), 24-ethylcholest-4,24(28)-dien-3beta-ol (8), respectively. Among them, 1 and 2 were new.
Nine compounds were isolated from the EtOH extraction of the twig of Carapa guianensis Aubl. On the basis of spectroscopic methods, their structures were elucidated as 1,3-di-benzene carbon amine-2-octadecylic acid-glyceride (1), hexacosanoic acid-2,3-dihydroxy-glyceride (2), ursolic acid (3), naringenin (4), scopoletin (5), 3,4-dihydroxymethylbenzoate (6), 2,6-dihydroxymethylbenzoate (7), tetratriacontanoic acid (8), triacontanoic acid (9) respectively. Among them 1 was new, 2 was firstly isolated from nature, and 3-9 were obtained from this plant for the first time.
The new triterpenoid taraxerol-3-beta-O-tridecyl ether was isolated from the aerial part of Derris triofoliata. The structure was established on the basis of spectral data.
Seven flavonoids, pongaflavone (1), karanjin (2), pongapin (3), pongachromene (4), 3,7-Dimethoxy-3', 4'-methylenedioxyflavone (5), millettocalyxin C( 6), 3,3',4', 7-tetramethoxyflavone (7), were isolated from 50% EtOH syrup of the bark of Pongamia pinnata and structureal elucidated on the base of spectral data. Compound 6 was isolated for first time from the plant of the genus Pongamia.
Sanya Bay encompasses a high diversity of natural habitats, ranging from coral reefs, rocky and sandy shores and mudflats to mangroves. Seasonal physicochemical and biological investigations were conducted from 1998 to 1999 and again in April 2000. Water-related environmental quality in Sanya Bay is in good condition. The levels of dissolved oxygen, nitrogen, phosphorus and heavy metals are within the first class of National Seawater Quality Standards for China. Annual mean values of chlorophyll a of 0.93 mg m(-3) and phytoplankton primary productivity of 440.8 mgC m(-2)d(-1), respectively, were found in the waters, both of which show a significant correlation with inorganic nitrogen. A mean new productivity of 144.6 mgC m(-2) d(-1) was recorded in summer. Sanya Bay is rich in natural resources and biodiversity with 235 species of phytoplankton and 129 species of zooplankton identified in the survey. The annual mean abundance of phytoplankton and zooplankton were 1564 x 10 cells m(-3) and 121 individuals m(-3), respectively, with an annual mean zooplankton biomass of 129 mg m(-3). A total of 243 species of fish were sampled in the survey including many of high economic value. Three hundred and eighty-four species of benthos in 121 families were found by mud sampling and trawling. The average biomass of benthic organisms was 11.55 gm(-2), with a density of 31 individuals m(-2). Molluscs were the dominant group, followed by crustaceans; coelenterates exhibited the lowest biomass. One hundred and twenty-six species from 48 families of intertidal organisms were collected by frame sampling, with a mean annual biomass of 644.7 gm(-2) and average density of 816 individuals m(-2). The highest biomass of 1673.5 gm(-2) was collected in a coral reef region, while the highest density of 1219 individuals m(-2) occurred in a mangrove region. The coastline is characterized by coral reefs that accounts for 30% of the total coastline length in the bay, so coral reefs are a key ecosystem that are important for maintaining the regional marine resources and biodiversity. We need to pay much more attention to such diverse marine resources to maintain the integrity and function of these coastal ecosystems.
A phenylethanoid glycoside (ilicifolioside A) and an aliphatic alcohol glycoside (ilicifolioside B), have been isolated from the aerial parts of Acanthus ilicifolius, together with eight known compounds. Their structures were determined from spectroscopic analyses.
Beta 1,4 galactosyltransferase 1 (beta 1,4GT1) synthesizes Gal beta 1-->4GlcNAc groups in N-linked sugar chains of animal glycoproteins, which have been demonstrated to play an important role in many biological events, including sperm-egg interaction, cell migration and mammalian embryonic development. In this study, the mRNA level of beta 1,4GT1 was found to increase greatly during the 7721 hepatocarcinoma cells apoptosis induced by cycloheximide. Ricinus Communis Agglutinin-I staining indicated generous increase of Gal beta 1-->4GlcNAc groups during apoptosis. Further study showed that the 7721 hepatocarcinoma cells transiently transfected with beta 1,4GT1 were more susceptible to the apoptosis induced by cycloheximide. The increased susceptibility was in accordance to the transfection concentration of beta 1,4GT1, which also led to the increased Gal beta 1-->4GlcNAc groups on the transfected cell surface. All the observations suggested that beta 1,4GT1 and Gal beta 1-->4GlcNAc groups might be associated with the apoptosis of human hepatocarcinoma cells.
From the aerial parts of Acanthus ilicifolius, a new aliphatic alcohol glycoside (ilicifolioside C) and two new (Z)-4-coumaric acid glycosides, (Z)-4-coumaric acid 4-O-beta-D-glucopyranoside and (Z)-4-coumaric acid 4-O-beta-D-apiofuranosyl-(1"-->2')-O-beta-D-glucopyranoside were isolated. The structural elucidations were based on the analyses of spectroscopic data. Z-Form 4-coumaric acid glycosides were first isolated from plant.
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The p58(PITSLRE) is a p34(cdc2)-related protein kinase that plays an important role in normal cell cycle progression. Elevated expression of p58(PITSLRE) in eukaryotic cells prevents them from undergoing normal cytokinesis and appears to delay them in late telophase. To investigate the molecular mechanism of p58(PITSLRE) action, we used the yeast two-hybrid system, screened a human fetal liver cDNA library, and identified cyclin D3 as an interacting partner of p58(PITSLRE). In vitro binding assay, in vivo coimmunoprecipitation, and immunofluorescence cell staining further confirmed the association of p58(PITSLRE) with cyclin D3. This binding was observed only in the G(2)/M phase but not in the G(1)/S phase of the cell cycle; meanwhile, no interaction between p110(PITSLRE) and cyclin D3 was observed in all the cell cycle. The overexpression of cyclin D3 in 7721 cells leads to an exclusively accumulation of p58(PITSLRE) in the nuclear region, affecting its cellular distribution. Histone H1 kinase activity of p58(PITSLRE) was greatly enhanced upon interaction with cyclin D3. Furthermore, kinase activity of p58(PITSLRE) was found to increase greatly in the presence of cyclin D3 using a specific substrate, beta-1,4-galactosyltransferase 1. These data provide a new clue to our understanding of the cellular function of p58(PITSLRE) and cyclin D3.
Minimal overexpression of the p58PITSLRE protein kinase in Chinese hamster ovary cells induces telephase delay, abnormal cytokinesis, retarded cell growth and apoptosis. Fas mediated T cell death is correlated with p58PITSLRE proteolysis and an increase in its histone H1 kinase activity. In this study, it was found that p58PITSLRE had different effects on the apoptosis induced by etoposide, cycloheximide and serum-withdrawal in human hepatocarcinoma cells. The ectopic expression of p58PITSLRE in human hepatocarcinoma cells suppressed apoptosis induced by etoposide, while enhancing the apoptosis induced by cycloheximide and serum-withdrawal respectively. Elevated expression of p58PITSLRE was found during the apoptosis induced by etoposide, whereas most of p58PITSLRE was proteolytically processed during apoptosis induced by cycloheximide and serum-withdrawal. Furthermore, transient transfection of p50PITSLRE resembling the proteolytic form of p58PITSLRE enhanced the 7,721 cells susceptibility to apoptosis induced by all the three stimuli. These findings suggest that the full-length p58PITSLRE might protect the cells from the apoptosis induced by etoposide and its proteolysis might contribute to and enhance the apoptosis induced by cycloheximide and serum-withdrawal respectively.
A new acylated flavonol glycoside, kaempferol 3-O-[(6''''-feruloyl)-beta-D-glucopyranosyl-(1 --> 3)]-[alpha-L-rhamnopyranosyl-(1 --> 6)]-beta-D-glucopyranoside and two known cyclolignan glycosides, (+)-lyoniresinol-3alpha-O-beta-D-glucopyranoside and ( - )-lyoniresinol-3alpha-O-beta-D-glucopyranoside were isolated from n-BuOH extracts of the aerial parts of Derris triofoliata, their structures were determined from spectroscopic and chemical evidences.